This invention pertains to methods and apparatus for aiding in the installation and removal of modules which are removably supported on a chassis.
Often, prior art electrical equipment, such as large computers and disk arrays, is comprised of various electronic and electrical components which are supported on a common structural support such as a chassis, or frame, or the like. These modular components, or modules, can be one of any number of different devices such as a disk drive, a controller, a power supply, or a cooling fan, etc. Generally, the modules are coupled to a signal and/or power distribution network which is supported on the chassis or support. This signal and power distribution network allows signals and/or power to be passed between each of the modules and other components which make up the electrical equipment.
Additionally, each of the modules is generally configured to be easily removable from, and installable into, the chassis or support. This configuration allows the removal or replacement of any of the modules in the event such removal or replacement becomes necessary or desired. To facilitate the removal from, and installation into, the chassis, a coupling is utilized to connect each of the modules to the signal and power distribution network. These couplings are often comprised of two mating portions. One of the portions is usually mounted on the chassis and the second portion is mounted on the module. When the module is placed on the chassis, the two portions of the coupling matingly engage each other to connect the module to the distribution network. Likewise, when the module is removed from the chassis, the two portions of the coupling disengage each other so as to disconnect the module from the distribution network. Often, the two portions of the coupling have a slight interference-fit to both ensure adequate contact between the coupling portions and to minimize movement of the coupling portions relative to each other when connected. As a result, a considerable amount of force is often required to overcome the interference-fit when both connecting and disconnecting the two coupling portions.
To aid in overcoming the force required to connect the coupling portions, prior art modules are equipped with latches. These latches are often essentially in the form of a simple lever which is mounted on the front of the module and configured to pivot about an axis which is fixed on the module. The latch comprises a short engagement portion on one side of the axis and a long handle portion on the opposite side of the axis. As the module is placed onto the chassis, the engagement portion of the latch engages the chassis. A manual force can then be applied to the handle portion of the latch. The configuration of the latch provides a mechanical advantage which multiplies the manual force which is applied to the handle portion. This force-multiplication provided by the latch allows for the interference-fit of the coupling to be easily overcome when installing or removing a module from the chassis.
FIGS. 1 through 3 help to illustrate the configuration and operation of a typical prior art latch for use with a module and chassis as described above. FIG. 1 is an exploded perspective view of a prior art unit 10. The unit 10 includes a chassis 12 which is configured to removably support one or more modules 14. Although four modules are shown, it is understood that the chassis 12 can be configured to support any number of modules 14. Each of the modules 14 has a latch 16 which is configured to engage the chassis 12 as the respective module is installed into the chassis.
FIG. 2 is a top view of the unit 10 depicted in FIG. 1, which shows one of the modules 14 partially inserted into the chassis 12, and the other module fully inserted into the chassis. As is seen, a first coupling portion 20 is mounted on each of the modules 14. Additionally, each first coupling portion 20 has a corresponding second coupling portion 21 which is mounted on the chassis 12. Each of the first and second coupling portions 20, 21 are positioned so that, when the respective module 14 is fully installed into the chassis 12, the coupling portions are connected to one another. As is also seen, each of the latches 16 is movably mounted on each respective module 14. As shown, each latch 16 is configured to pivot, relative to the respective module 14, about a pivot point 17. Each of the latches can pivot along an arc indicated by the arrows 18.
FIG. 3 is another top view of the unit 10 which is depicted in FIG. 1. As shown in FIG. 3, one of the modules 14 has been fully installed into the chassis 12. If the latch 16 of the fully installed module 14 is pulled in the direction indicated by the arrow 26, then the module will be pulled slightly out of its fully installed position so that the coupling portions 20, 21 are nearly completely disconnected from one another. This is illustrated by the position of the other module 12 which is shown in FIG. 3. If the latch 16 of this other module 14 is moved in the direction indicated by the arrow 24, then the latch will engage the chassis 12 and the module 14 will be pushed fully into the chassis, whereupon the first and second coupling portions 20, 21 will fully connect. It is noted that the installation of the module 14 into, and removal of the module from, the chassis 12 is assisted in each case by the lever-action of the respective latch 16. That is, because of the off-set location of the pivot point 17 relative to the respective latch 16, the latch provides a mechanical advantage which aids in overcoming the force required to connect and disconnect the connector portions 20, 21 when installing and removing the module 14.
However, one problem associated with the prior art latch design is that it can cause a disruption of the operation of the modules 14. More specifically, if the latch 16 is pulled in the direction indicated by the arrow 26 shown in FIG. 3 while the module is operating, then the movement of the first and second coupling portions 20, 21 relative to one another can cause electrical noise and arcing. This electrical noise can disrupt the operation of the module 14. In the case in which the module comprises a controller or disk drive, for example, the disruption can include the loss of data, which is highly undesirable.
Preferably, the module 14 proceeds through a shut-down sequence prior to any movement thereof relative to the chassis 12. The shut-down sequence prepares the module 14 for disconnection from the distribution network, which prevents adverse effects associated with the disconnection of the coupling portions 20, 21 as described above. The shut-down sequence can be initiated by manual activation of a switch (not shown) located on the respective module 14 or on the chassis 12. However, disruption of the operation of the modules 14 can still occur if the respective latch 16 is inadvertently pulled without first activating the switch to initiate the shut-down sequence.
In some prior art equipment, various forms of mechanical interlocks (not shown) have been employed in an attempt to prevent inadvertent movement of the module 14 relative to the chassis 12, which in turn, would theoretically prevent the disruption of the operation of the module. However, in most cases, the interlocks still allow slight movement of the module 14 relative to the chassis 12 when the respective latch 16 is inadvertently pulled. This slight movement of the module 14 caused by the latch 16 is, in most cases, enough to cause disruption of the operation of the module. Additionally, the mechanical interlocks ad a considerable amount of complexity and bulk to the unit 10. What is needed, then, is a latch apparatus for use with a unit of electrical equipment in which the inadvertent movement of the module prior to initiation of the shut-down sequence is prevented.
Therefore, it is desirable to provide a latch apparatus which achieves the benefits to be derived from similar prior art devices, but which avoids the shortcomings and detriments individually associated therewith.
In accordance with a first embodiment of the present invention, a module removal system includes a latch assembly which is movably mounted on a module. The latch is configured to move so as to contact a chassis on which the module is supported in order to aid in removal and installation of the module. A sensor is also mounted on the module and configured to detect a given movement of the latch with respect to the module. The given movement of the latch occurs before the latch contacts the chassis. The sensor can send a signal to the module which enables the module to take appropriate measures in anticipation of disconnection and removal from the module.
In accordance with a second embodiment of the present invention, a module removal system includes a latch assembly which comprises an engagement portion which is rotatably mounted on a module, and a target portion which is rotatably mounted on the engagement portion. The engagement portion is configured to move so as to contact a chassis on which the module is supported in order to aid in removal and installation of the module. A sensor is mounted on the module and is configured to detect the presence of the handle portion when the latch is placed in a given position relative to the module. In the given position, the latch is prevented from moving relative to the module by the engagement of the target portion with the module.
In accordance with a third embodiment of the present invention, a module removal system includes a latch assembly which comprises an engagement portion and a target portion connected to the engagement portion, and wherein both are rotatably mounted on the module about a common axis. The engagement portion is configured to rotate so as to contact a chassis on which the module is supported in order to aid in removal and installation of the module. Movement of the target portion relative to the engagement portion is limited by a projection defined on the target portion which extends into a slot defined on the engagement portion. The projection is movably contained within the slot so as to limit the movement of the target portion relative to the engagement portion. The apparatus also comprises a sensor mounted on the module and configured to detect a given movement of the target portion. Movement of the target portion beyond the given movement causes rotation of the engagement portion.
In accordance with a fourth embodiment of the present invention, a module removal system includes a latch assembly which comprises an elongated engagement portion which is rotatably mounted on a module. Rotation of the engagement portion aides in the removal and installation of the module which is removably supported on a chassis. The latch also comprises a target portion which is slidably mounted on the engagement portion. The target portion includes a lock member defined thereon which is configured to engage with the module so as to substantially prevent rotation of the engagement portion relative to the module. The apparatus also includes a sensor which is mounted on the module and which is configured to detect the presence of the lock member when it is engaged with the module.
In accordance with a fifth embodiment of the present invention, a module removal system includes a latch assembly which comprises an engagement portion which is rotatably mounted on a module. The module is removably supported on a chassis and rotation of the engagement portion aids in the installation and removal of the module. The latch apparatus also comprises a target portion which is rotatably mounted on the engagement portion and which rotates about a secondary axis. A lock member is mounted on the target portion and configured to rotate therewith. The lock member can be engaged with the module when the engagement member is placed in a given position relative to the module. The engagement of the lock member with the module substantially prevents the rotation of the engagement member. The latch apparatus also comprises a sensor which is mounted on the module and is configured to detect the presence of the lock member when the lock member is engaged with the module.
In accordance with a further embodiment of the present invention, a method is disclosed of removing a module from its supported position on a chassis. The method includes moving a target portion of a latch assembly and detecting the movement thereof. The method also includes moving an engagement portion of the latch assembly after movement of the target portion. Movement of the engagement portion causes movement of the module. The method can further include generating a signal as a result of the detection of the movement of the target portion and can further include terminating the intended operation of the module in response to the signal.